The present invention relates to tires. More particularly, it relates to a tire, in particular for a vehicle of the two-wheeled type, comprising an anti-vibration means.
In vehicles of the two-wheeled type, such as motorcycles, scooters and others, the different types of vibration such as those originating from the engine, from travel, imperfections in the road, etc, are difficult to dampen, so they are for the most part transmitted to the occupants of the vehicle. These vibrations may occur in the vertical, longitudinal or transverse directions. The result may be a certain amount of discomfort, which may itself be a source of fatigue if use is prolonged, in particular if the levels of vibrations are rather high.
The designers of such vehicles therefore use considerable means to tackle the problem of vibrations. The manufacturers of the various elements of the vehicle are not passive bystanders in this either, since each can contribute to a greater or lesser extent to attenuating or dampening the induced vibrations, or even better, to eliminate them at source. To this end, tire manufacturers may play a decisive part as far as the vibrations due to travelling and to imperfections in the road are concerned. The front tire may constitute a key element in this respect.
The reinforcement of the carcasses of tires at present consists of one or more plies (conventionally referred to as “carcass plies” owing to the process of manufacturing in the form of semi-finished products in the form of plies), provided with cord reinforcements which may be radial. The anchoring or holding of these plies or reinforcements is effected conventionally by turning up a portion of the ply around a bead wire arranged in the bead of the tire.
Furthermore, there are nowadays tires that do not have the conventional upturn of the carcass ply around a bead wire, or even a bead wire, in the conventional sense of this element. For example, document EP 0 582 196 describes a manner of arranging a carcass type reinforcement in the beads, by arranging circumferential filaments adjacent to said reinforcement structure, the whole being embedded in an anchoring or bonding rubber mix, preferably of high modulus of elasticity. Several arrangements are proposed in this document. This document furthermore makes reference to tires manufactured without the aid of semi-finished products in the form of plies. For example, the cords of the different reinforcement structures are applied directly to the adjacent layers of rubber mixes, and are applied in successive layers on a core. The core has a shape that makes it possible to obtain directly a profile similar to the final profile of the tire being manufactured. Thus, in this case, rather than “carcass plies” in the conventional sense, we have more specifically “reinforcements of carcass type.” This term, which in fact designates the reinforcements of one or the other type, will be used in the present document.